A quick guide to identifying Mikuni carbs
One of the most common questions I get is what size Mikuni do I have? But, with the flood of "fake" Mikunis hitting the market, maybe of the first questions should be, is my Mikuni really a Mikuni? So, let's begin with determining if your carb is really a Mikuni.
A bit of history
The Mikuni round-slide carburetor is one the most used carburetors in the history of carburetors - motorcycle and otherwise. For nearly 60 years, some variation of this carb has been mounted on hundreds of thousands of motorcycles made in Japan, USA, England, Italy, Germany, India, Brazil and a host of other countries. No wonder there are so many people making knockoffs. Mikuni began building carbs in the 1950s. The carburetors they manufactured were a licensed copy of an Amal carburetor. Amal is a British carburetor and their carbs were mounted on almost all British bikes Mikuni rightly determined that design could be improved upon, and they did a fantastic job designing their own.
One notable product imported by Mikuni Shoten (their original name) before the end of World War II was Moto Guzzi motorcycles, particularly those with sidecars. In pre-war Japan, even as development carried on at a frantic pace, the roads were not the best, so motorcycles with sidecar rigs were highly valued, for both civilian and military purposes. In 1932, Mikuni began producing Amal and Galery carburetors under license in Japan, and began supplying the nascent Japanese motorcycle and automobile industry.
In a curious footnote to automotive history, Mikuni Shoko (the company has changed its name and corporate status many times) manufactured small gasoline-powered generators for wireless radios for the Imperial Army. After the war, Soichiro Honda came upon one of the engines and was inspired to mount it on a bicycle. After working out the kinks, he visited Mikuni’s two factories and bought their remaining supply of around 500 No. 6 Wireless Radio Generator Engines. Though not the most reliable motorcycle engine, it inspired the founding of Honda Motor Company in 1948.
Post-war Japanese corporate reconstruction law split Mikuni into two entities in 1948, though they merged again in 1955. Not long after, in 1960, Mikuni acquired the rights to produce Solex sidedraft-type carburetors in Japan. The agreement with Solex included a 25-year term where the Solex name had to be on the carburetors. Over the years, the French maker’s name got smaller and smaller as the “Mikuni Kogyo Made In Japan” wording got larger. But it was just not the name that became more prominent. Mikuni was constantly improving on the licensed design, from producing a superior casting for the main bodies to improving the accelerator pump assemblies to general improvements overall. When the Solex name was dropped in 1985, the PHH carburetors were more Mikuni than Solex.
Though multiple-carb setups were not common on OEM applications of cars exported to the U.S., some models, such as the Toyota Celica with the OHC 18R-G engine, had a pair of Mikuni dual-throat sidedraft carburetors available. Well into the 1970s and 1980s, some Mitsubishi cars and trucks, including some of those sold as Dodge or Plymouth models, carried Mikuni carbs. Even the optional, Mitsubishi-made 2.6-liter engine found in the Chrysler K-cars used an electronic version of a Mikuni carburetor.
But it was the aftermarket, particularly in the high-performance and racing areas, that saw significant adoption of Mikuni sidedraft carburetors. Datsun 510s, using a pair of the carbs, and 240Zs, using a three-carb setup for their six-cylinder engines, were some of the most notable vehicles to be treated to the free-breathing PHHs. Though the PHH has been out of production for about two decades, some parts and rebuild kits can still be found. Likewise, the quality of Mikuni’s original castings and manufacture mean that they are still worth rebuilding. Here in the United States, Wolf Creek Racing of Long Island, New York, still maintains a robust business dealing with Mikuni carburetors for vintage Nissans and Datsuns.
Mikuni Corporation continues to operate its import and export ventures. Mikuni American imports carburetors for the aftermarket for snowmobiles, personal watercraft and motorcycles, surprisingly enough enjoying a fair amount of success with its units for Harley-Davidson and similar big twins. The same company exports parts for the Japanese aerospace and defense industries, a significant share of Mikuni’s business operations.
A bit of history
The Mikuni round-slide carburetor is one the most used carburetors in the history of carburetors - motorcycle and otherwise. For nearly 60 years, some variation of this carb has been mounted on hundreds of thousands of motorcycles made in Japan, USA, England, Italy, Germany, India, Brazil and a host of other countries. No wonder there are so many people making knockoffs. Mikuni began building carbs in the 1950s. The carburetors they manufactured were a licensed copy of an Amal carburetor. Amal is a British carburetor and their carbs were mounted on almost all British bikes Mikuni rightly determined that design could be improved upon, and they did a fantastic job designing their own.
One notable product imported by Mikuni Shoten (their original name) before the end of World War II was Moto Guzzi motorcycles, particularly those with sidecars. In pre-war Japan, even as development carried on at a frantic pace, the roads were not the best, so motorcycles with sidecar rigs were highly valued, for both civilian and military purposes. In 1932, Mikuni began producing Amal and Galery carburetors under license in Japan, and began supplying the nascent Japanese motorcycle and automobile industry.
In a curious footnote to automotive history, Mikuni Shoko (the company has changed its name and corporate status many times) manufactured small gasoline-powered generators for wireless radios for the Imperial Army. After the war, Soichiro Honda came upon one of the engines and was inspired to mount it on a bicycle. After working out the kinks, he visited Mikuni’s two factories and bought their remaining supply of around 500 No. 6 Wireless Radio Generator Engines. Though not the most reliable motorcycle engine, it inspired the founding of Honda Motor Company in 1948.
Post-war Japanese corporate reconstruction law split Mikuni into two entities in 1948, though they merged again in 1955. Not long after, in 1960, Mikuni acquired the rights to produce Solex sidedraft-type carburetors in Japan. The agreement with Solex included a 25-year term where the Solex name had to be on the carburetors. Over the years, the French maker’s name got smaller and smaller as the “Mikuni Kogyo Made In Japan” wording got larger. But it was just not the name that became more prominent. Mikuni was constantly improving on the licensed design, from producing a superior casting for the main bodies to improving the accelerator pump assemblies to general improvements overall. When the Solex name was dropped in 1985, the PHH carburetors were more Mikuni than Solex.
Though multiple-carb setups were not common on OEM applications of cars exported to the U.S., some models, such as the Toyota Celica with the OHC 18R-G engine, had a pair of Mikuni dual-throat sidedraft carburetors available. Well into the 1970s and 1980s, some Mitsubishi cars and trucks, including some of those sold as Dodge or Plymouth models, carried Mikuni carbs. Even the optional, Mitsubishi-made 2.6-liter engine found in the Chrysler K-cars used an electronic version of a Mikuni carburetor.
But it was the aftermarket, particularly in the high-performance and racing areas, that saw significant adoption of Mikuni sidedraft carburetors. Datsun 510s, using a pair of the carbs, and 240Zs, using a three-carb setup for their six-cylinder engines, were some of the most notable vehicles to be treated to the free-breathing PHHs. Though the PHH has been out of production for about two decades, some parts and rebuild kits can still be found. Likewise, the quality of Mikuni’s original castings and manufacture mean that they are still worth rebuilding. Here in the United States, Wolf Creek Racing of Long Island, New York, still maintains a robust business dealing with Mikuni carburetors for vintage Nissans and Datsuns.
Mikuni Corporation continues to operate its import and export ventures. Mikuni American imports carburetors for the aftermarket for snowmobiles, personal watercraft and motorcycles, surprisingly enough enjoying a fair amount of success with its units for Harley-Davidson and similar big twins. The same company exports parts for the Japanese aerospace and defense industries, a significant share of Mikuni’s business operations.
